How Ammonium Valeric Acid Iodide Additive Can Lead to More Efficient and Stable Carbon‐Based Perovskite Solar Cells: Role of Microstructure and Interfaces?

• Published in: Solar RRL 2024-09, Vol.8 (17), p.n/a
• Main Authors: Perrin, Lara, Planes, Emilie, Shioki, Takaya, Tsuji, Ryuki, Honore, Jean‐Claude, Farha, Cynthia, Ito, Seigo, Flandin, Lionel
• Format: Article
• Language: English
• Subjects: 2D/3D perovskites; carbon‐based mesoscopic architectures; Chemical Sciences; degradation mechanisms; interfaces; Material chemistry; perovskite solar cells
• ISSN: 2367-198X; 2367-198X
• DOI: 10.1002/solr.202400393

As perovskite photovoltaic devices can now compete with silicon technology in terms of efficiency, many strategies are investigated to improve their stability. In particular, degradation reactions can be hindered by appropriate device encapsulation, device architecture, and perovskite formulation. Mesoporous device architectures with a carbon electrode offer a plausible solution for the future commercialization of perovskite solar cells. They represent a low‐cost and stable solution with high potential for large‐scale production. Several studies have already demonstrated the potential of the mixed 2D/3D ammonium valeric acid iodide‐based MAPbI3 formulation to increase the lifetime of pure MAPbI3. They can however not describe the mechanisms responsible for the lifetime improvement. Using a full set of characterization techniques in the initial state and as a function of time during damp‐heat aging, new insights into the performance and degradation mechanisms may be observed. With (5‐AVA)0.05MA0.95PbI3, the solar cells are very stable up to 3500 h and the degradation of performances essentially results from the loss of electrical contacts mainly located at the interfaces. In contrast, for the neat MAPbI3, a poor stability is evidenced (T50 = 500 h) and the loss in performance results from the degradation of the bulk perovskite layer itself. In a detailed study, new insights are enabled into the performance and the degradation mechanisms of carbon‐based mesoscopic perovskite solar cells. Even if ammonium valeric acid iodide‐based perovskite highlights a higher potential for species diffusion and interface contamination (highlighted by the dependence of the current‐voltage characteristics on the scan rate), they also perform better and longer.